Films based on books take 44% more at the box office | The Bookseller

The research found that films based on books took 44% more box office revenue in the UK (£5.4m) and 53% more globally ($91m or £68m) than those based on original scripts.
Meanwhile, 43% of the top 20 box office-grossing films in the UK between 2007 and 2016 were based on books, with a further 9% based on comic books.

The report reads: "In short, published material is the basis of 52% of top UK films in the last 10 years, and accounts for an even higher share of revenue from these leading performers, at 61% of UK box office gross and 65% of worldwide gross.